Your MX490 Series printer has an option that helps prevent misprints by detecting the size of the paper loaded into the cassette.
Solution
Your MX490 Series printer has an option that helps prevent misprints by detecting the size of the paper loaded into the cassette. If you want to disable this option, follow the steps below. Please note that disabling this option may cause misprints if the paper loaded into the cassette does not match the size you have specified on your computer or the printer itself.
Press the Setup button.
In the Setup menu, use the buttons to select Device settings. Press OK.
In Device settings, use the buttons to select Cassette settings. Press OK.
In Cassette settings, use the buttons to select Det. paper mismatch. Press OK.
Use the buttons to select OFF. Press OK.
To re-enable this setting, follow the steps above but choose ON in step 5.